- Simple Machines
Build a tower that can support a tennis ball at least 18 inches off the ground while withstanding the wind from a fan.
- Building surface (tray, cardboard, or piece of wood)
- Electric fan
- Paper (copier paper and/or newspaper)
- Tape (masking or duct)
- Tennis ball
- Wooden skewers or Popsicle sticks
BRAINSTORM AND DESIGN
Divide into teams of two or three. Before you begin designing, brainstorm answers to the following questions. Record and sketch your ideas in your design notebook.
- How can we use our materials to make a tower that's at least 18 inches tall?
- How can we use flexible materials, such as paper and string, to make a tower that is strong enough to hold up a tennis ball?
- How can we keep our tower from tipping over?
- How will we design our tower to resist the push of the wind and the pull of gravity?
As you brainstorm designs for your tower, think about other structures and how they stand up. For example, a tent combines flexible and rigid materials to make a frame and covering that can stand on its own.
BUILD, TEST, AND REDESIGN
Once you've got a tower to test, put it one foot away from the fan. (If your tower is hard to move, bring the fan over to the tower.) See how your tower responds when you turn the fan speed on low. When we made ours, we had to debug some problems. For example, our tower tipped over, our tennis ball kept falling off, and the weight of the tennis ball bent our tower. If any of these things happen to you, figure out a way to fix the problem so that your tower works as expected.